Raking apparatus for ore-roasting furnaces



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J. o. STEWART. Baking Apparatus for Ore Roasting Furnaces. No.236,274..A -Patentevd Jan. 4,1881. A

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N,FETERS. FHOT0-L|THOGRAPHEN, WASHMGTON. D C4 yJ. O. STEWART. BakingApparatus for Ore Roasting Furnaces. No. 236,274. Y Patented Jvan.4,1881..

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MPEYERS. PHOTLITHUGHAFHER, wASmNGTON. i7. C.

Y' l' UNITED STATES PATENT JAMES O. STEWART, OF ALAMEDA, CALIFORNIA.

RAKING APPARATUS FOR ORE-ROASTING FURNACES.

SPECIFICATION forming part of Letters Patent No. 236,274, dated January4, 1881.

' Application filed December 18, 1879.

VRoasting Furnaces; and 1 do hereby declare that the following is afull,clear, and exact description thereof, reference being had to theaccompanying drawings.

My invention contemplates improvements 4in raking apparatus forore-furnaces; and it consists of rakes having tubular handles andtubular and perforated heads, an upright tube having valves adapted tobe acted on by tubular cross-bars of the rakes, a iiexible hose orair-tube, and a blower, combined with an orefurnace, substantially ashereinafter more fully set forth.

Referringr to the accompanying drawings, Figure l is a side elevationwith a part of the outer wall removed. Fig. 2 is an end View taken fromthe left-hand side of Fig. l, with the outer wall broken away. Fig. 3 isa detail view of the rectangular hearth tubes. Figs. 4 and 5 are detailviews of the rakes. Fig. 6 is a vertical transverse section through linew a', Fig. 2.

A represents the body ofthe furnace, which is built square orrectangular and of the desired height, and is provided with afeed-hopper, B, on its top. Inside of this furnace I place one or moretubular hearths, G, at the desired distance above eachother, as shown.Each floor is made of a number of square tubes, C C', which are placedclose together, so as to form a continuous surface or door, While eachtube seggs is aconductqr of heat, as hereinafter described. The furnaceis'huilt with a double Wall on two of its sides, and the two walls oneach side are far enough apart to form narrow side chambers betweenthem. The hollow tubes, which form the floors ofthe furnace, passthrough the inner walls, E, and are supported by them, while the outerwalls, F, are solid. walls I also divide up, as hereinafter described.

Instead of building a singie fire-place entirely across one side of thefurnace, I employ two tire-places, G G', one on each side of thefurnace. The fire-place on one side extends from the front to near themiddle of the fur- The space between these two nace, while thefire-place on the opposite side extends from near the middle of thefurnace to its rear side, as shown. I then divide the spaces between thedouble side walls into two separate chambers by means of uprightpartitions H, so as to compel the heat from each fire-place to passupward through the tubes on its own half of the furnace. These sidespaces I again divide by horizontal partitions I, so as to compel theheat and products of combustion to pass back and forththrough the tubesin alternate directions until they reach the upper series of tubes,where the upright partition H terminates, so as to allow the heat andproducts of combustion from both fireplaces to mingle and pass throughthe upper set of tubes to the chimney or stack J.' This gives a uniformheat throughout the furnace and prevents the products ot' combustioncoming in contact with the ore. The ore, as it passes through the hopperB,lfalls upon the upper floor, and is stirred and moved by the rake,hereinafter described, until it falls through an opening, d, at the rearof the floor upon the next lower floor. Here the next rake takes it in alike manner, and rakes and moves it along over the iioor to the frontside of the furnace, where it falls through an opening upon the nextlower floor, andl so on down from one floor to the other, being rakedand stirred on each iioor in the same manner until. Vit is nailydischarged at the bottom.

Workin g-doors are made at the front of the furnace opening into eachore-chamber. Sliding doors are also placed over the opening in eachfurnace-hearth', through which the ore is discharged from hearth tohearth and to the receptacle beneath, so that either can be closed, asdesired, in order to retain the orea longer or shorter period on thehearth.

The ore-chambers between the tubular floors are each connected with achimney or stack, K, on one side of the furnace, into and through whichthe gases generated by the heat in the roasting-chambers are drawn oft',thus forming a complete muftle-furnace.

My mechanical stirring apparatus consists of a frame-work constructed atthe .rear of the Y.

furnace. This frame has two or more horizon- IOO ranged to slide. Thecross-heads are connected together by an upright framefwork, N, and theentire framework and cross-heads are moved back and forth toward andfrom the furnace by a crank, O, which is driven by suitable power. Therake-heads e and their handles f are tubular, ordinary gas-pipe servingfor the handles, and thehandles pass through the upright sliding frameN, and are secured to it by set-screws b, so that when the rake-headsare placed in the ore-chambers and their handles extend out horizontallyand are attached to the sliding frame the rakes will be caused to movesimultaneously back and forth over all the noors when the sliding frameis moved. The rakes are represented in the present instance with twohandles, and the outer ends of these handles are connected by a tubularcross-bar, s, which projects to one side, as shown.

P is a vertical tube, which is attached to the sliding frame, so as tomove with it, and its upper end is connected with a blower, O. by atiexible hose, It. The tube P has a number of valves, t, occupyingcoincident positions with and adapted to be held open by projectingportions of the rake cross-bars s. valves t open, the cross-bars of therakes are adjusted and secured by means ofthe set-screws b against andso as to press the said valves inwardly. rIhe rake-heads, as stated, arealso tubular, so that when the rakes are fixed in their raking positionair will be forced by the blower through the flexible tube R, verticaltube P, cross-bar s, tubular handles f, into the tubular rake-heads, andthence, through minute holes or pertorations in the under side of therake-head, into and upon the orc while it is being stirred.

Should it be desired to put out of operation any one or more of therakes, it is only necessary to loosen its set-screws and move it by itshandles until the cross-bar of the handles is sufficiently removed fromthe carrying-frame as to prevent contact therewith as the frame travelsback and forth with and is operating the other rakes. The valve t isthen closed, after which the remaining rakes can be operated in the samemanner as above described. The air is thus delivered through therakehead so as to impinge directly into and upon the ore infinely-divided streams as the rakes stir it up and turn it over, so thateveryparticle of ore is thoroughly oxidized. The air passing' throughthe handles keeps them cool,

To hold the and at the same time the air is partially heated before itstrikes the ore, so that the temperature of the furnace is notinterfered with.

This stirring apparatus and blower can be used in any furnace having oneor more dat hearths-such as the ordinary reverberatory furnaceand byproperly shaping the raketeeth they can be made to stir the ore, andalso to move it forward continuously to the discharge-openings, stirringand discharging at the same time.

A moditcation ot' myt'urnace is applied when it is desired to allow theproducts of combustion from the tire-place to mingle with the gases fromthe ore-cham ber. ln this case I use only one fire-place, extendingentirely across one side ofthe furnace, and instead ot' making thehearths or tloors of tubes, I leave the ends ofthe tubes` where theyrest in the wall, tubular; but I cut away the under side of the tubesbetween the ends, so that the products of conlbustion and gases canmingle. This form of hearth-tubes I call open-bottom tubes.7

I am aware that it is old to construct a furnace with end fines andalternate series of tubular hearths and ore-chambers, and with tireboxeslocated diagonally opposite to each other, the products of combustion ofwhich are confined to their respective halves or sides of the furnaceand caused to pass tortuously through the tubes or hearths to andthrough a common tube.

I am further aware that it is old to rake or stir the contents ofafurnace and to pass simultaneously into said contents air or a blastthrough the alie.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

rlhe raking apparatus constructed of the rakes ef, having tubularhandles and tubular and perforated heads, the upright tube P, havingvalve t, acted upon by tubular cross-bars s of the rakes, the ticxibletube or hose R, and the blower Q, in combination with the furnace A,substantially as and for the purpose set forth.

In witness whereot` I have hereunto set my hand and seal.

JAMES 0. STEWART. [L. s]

itnessesz W. F. I. CLARK, EDWD. E. OsBoRN.

